It is well known that perishable or oxidizable foods may be preserved by controlling the oxygen and carbon dioxide content of the atmosphere in which the food is stored and that quality of stored foods may be improved by removal of other odours and gases from that atmosphere.
1. Field of the Invention
This invention has particular application to food storage systems which reduce the oxygen content of the gas within the storage system by combining the oxygen with a hydrocarbon gas and subsequently removing the carbon dioxide by passing the storage gas over a charcoal adsorber.
2. Description of the Prior Art
Canadian Pat. No. 794,298 issued in 1968 describes a process for treating the storage gas by passing it through a combustor, that is a catalytic devise for combining the oxygen with a hydrocarbon gas, and for further treating the storage gas by passing it through an adsorber consisting of activated charcoal. For continued processing, it is necessary that the activated charcoal adsorber be regenerated by passing atmospheric air through the adsorber to remove the carbon dioxide. Canadian Pat. No. 1,128,810 issued Aug. 3rd, 1982 discloses a process for avoiding the introduction of atmospheric air from the adsorber when the adsorber is once more connected to the food storage chamber after regeneration. In the process described in this patent, the adsorber chamber is refilled with gas from the storage chamber and the atmospheric air is displaced from the adsorber chamber into the atmosphere before the adsorber chamber is reconnected to the storage chamber. It will be noted that because the storage chamber is sealed and the gas in the adsorber chamber is displaced by gas from the storage chamber, the volume of gas thus displaced must be extracted from the storage chamber. This must of necessity cause a reduction of pressure in the storage chamber. Subsequently, when the adsorber chamber is to be reconnected to atmosphere, atmospheric air is introduced into the adsorber chamber and the gas from the adsorber chamber is reintroduced into the storage chamber. Here, once again, a variation in pressure in the storage chamber must be produced. It will be seen therefore that variations in the pressure in the storage chamber must be caused by this mode of operation. Such variations in pressure clearly must encourage leakage into the storage chamber. Since the storage chamber is a large chamber and, in many cases, is merely a modified refrigeration chamber, which must permit introduction and removal of food from the chamber, the chamber cannot be perfectly sealed and any variation in pressure within the chamber with reference to the ambient atmospheric pressure will produce undesirable leakage and introduction of oxygen from the ambient atmosphere.